1. Field of the Invention
The present invention relates to an immersion microscope objective and a microscope provided with it.
2. Description of the Related Art
Fluorescent observation is widely known as a method for observing a living body. Fluorescent observation is a method for observing a specimen by applying excitation light to a living body specimen to which a tag is attached by fluorescent dye and detecting fluorescent light generated from the fluorescent dye. The fluorescent dye is selectively combined with a specific molecule and a component object in the living body specimen and dyes them. Therefore, the behavior, combination state, movement state and the like of molecules in the specimen can be observed in addition to the structure of the specimen by detecting the fluorescent light.
Traditionally, the burden on a specimen due to dyeing with fluorescent dye has been heavy and living body targets that can be observed while living have been limited to a cell's level, such as a culture cell, and the like. However, recently, a fluorescent protein which can be expressed in a cell by introducing a gene has been put into practical use and damage to the living body specimen can be reduced by using this protein. GFP (green fluorescent protein), YFP (yellow fluorescent protein) or the like are examples of such a protein. The number of targets of fluorescent observation has been expanded by the commercialization of these fluorescent proteins and currently various living body specimens can be observed.
Japanese Laid-open Patent Publication No. 10-274742 discloses an immersion microscope objective usable for such a fluorescent observation.